Apparatus for and method of cleaning and partially dehydrating oily wood preservatives



March 16, 1943- J. A. VAUGHAN ETAL 2,314,257 APPARATUS FOR AND METHOD OF CLEANING AND PARTIALLY DEHYDRATING OILY WOOD PRESERVATIVES Filed Aug. 16, 1941 V gwuc wtold JA.

Patented Mar. 16, 1943 use Joseph A. Vaughan and Joseph C. Vinson, At

lanta, Ga., assignors to Southern Wood Pre= serving Company, Atlanta, Ga., a corporation of Georgia Application August 16, 1941, Serial No. 407,212 9 Claims. (01. 196-146) The present invention provides an improved and novel apparatus for and method of removing the insoluble matter from and simultaneously partially dehydrating oily wood preservatives, such as used, as well as fresh coal-tar, coal-tar creosote, coal-tar creosote mixtures and mixtures of coal-tar with coal-tar creosote or coal-tar creosote with petroleum products. One of the main objects is to remove A, B and C insolubles which are well known in the wood preserving art as the actual insoluble, benzol precipitated insoluble and water-soluble foreign matter, respectively, thereby increasing the Wood penetrating quality of the preservatives. A further object is to partially dehydrate the products to be processed. A still further object is to clarify the oily wood preservatives so that, in the subsequent treatment of wood with these preservatives, the wood will be left clean and of a light color and bleeding of the preservative from the treated wood will be minimized.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawing, wherein the figure is a diagrammatic illustration of apparatus for practicing the method.

This invention takes advantage of a means of bringing finely divided oily preservative in contact with a washing medium, usually water or a water solution of calcium chloride, sodium chloride, calcium hydroxide, sodium hydroxide or the like in such manner as to form a mixture or emulsion. The chemicals are used to vary the pH value of the solution and also to hasten coalescence of one of the liquid phases. During the process, the emulsion partially separates, due to coalescence of one of the liquid phases, thus allowing the larger portion of the oily preservative to separate from the mixture or emulsion, leaving behind, in the unseparated emulsion, a majority of its A and B insoluble matter and, at the same time, the water-soluble foreign matter is dissolved in the wash solution.

The method is most effective in the treatment of an oily wood preservative of the character already mentioned which has been used in the treatment of forest products and has accumulated some dirt, additional free carbon or high carbon content hydrocarbons (insoluble in benzol), sugars, starches, gums, resins, rosin and the like, as well as some water, which mixes with the preservative and forms an emulsion, aided by one or more of the emulsifying agents present. Some of these matters or compounds are watersoluble; whereas others are oil-soluble and still may be water ore. water solution of one or more of the aforesaid chemicals.

Now, if such a preservative is sprayed or injected into a mass of water or an aqueous solution, the preservative will break up into finely divided particles which, in passing through the water solution, will be washed or scrubbed. The water-soluble foreign materials in the preservative will thus be dissolved bythe excess water coming in cont'actwith the finely divided g'lobules' or mist of the preservative and, due to the greatly increased surface of the emulsion, colloid or mixture, and to the excess of the wa-- ter phase, coalescence of practically the entire body of waterwill be" produced, thus separating water from the preservative; In addition, the 1ow'-preservative=content emulsion will hold the so-ca-lled'b'enzo1insolubles, allowing the clean oily preservative to separate and be discharged from the system. The water cit mtainingthewater-sol-- uble foreign matter will accumulate in a separate stratum and maybe discharged at another point in the system' and the accumulated sludge, or low-preservative content emulsioncarrying the so-called benzo-r insoluble, will settle in another stratum and maybe periodically discharged at a third point in the system.

Referring particularly to the illustrative apparatus shown in the drawing, the preservative to be processed is placedin a storage tank" I from which it is delivered toa" processing tank 2 through a valved conduit 3; In this instance, it is delivered under a pressure 25 pounds 50 pounds gage by a pump 4 and the quantity may be" measured by a meter 5; The conduit is-shown asnaving a flexible h'OS'e S e'Ct-iOfi 6 ccnne'cteu to a spray head I when may be similar to an ordi nary baths'how'er Head or it is contemplated that asuitable spray nozzle may be employed. The head is suitablymo'urited in a float 8 in the processing tanl and fresh water is supplied through avalved pipe 9, here shown as also extending through tlie" float and having a bent end [0' to direct thewa't er below the spray head. However, thewater pipe may be otherwise connec't'ed to the tank. g

The processing tank is shown as having valved rain conduits l1 and 12} connected atdiff'rent 1eve1s; the 11131581 conduit eing" arranged tb'diain xce'ss'wash water containing" water-soluble for- Suchpreferably heated to a temperature ranging be tween 150 and 200 F. In this example, separate steam heating coils I1, 18, l 9 and 20 are arranged in the processing tank, the coil 20 being employed to keep the cleansed oily preservative in a liquid state; while the other coils l1, l8 and I9 are conveniently located in the different strata for the purpose of maintaining predetermined temperatures in the strata.

If in the treatment of used creosote, the time required for complete cleansing and partial dehydrating is approximately 10 hours and it is desired to treat, say, 500 gallons per hour, then the creosote will be charged into the processing tank at the rate of 500 gallons per hour for a period of ten hours, after which the processed oily preservative will begin to be withdrawn at the same rate, as the. charging rate. From this point on, the treatment is continuous.

It is contemplated that the process may be practiced either continuously or intermittently. The fresh water may be supplied more or less continuously to replace sludge that is drained from the processing tank and maintain the desired level and quantity in the tank. The size and height of the processing tank are such that the finely divided spray will have ample opportunity to emulsify and the separated constituents to stratify or settle at different levels. It will be understood that the height of the drain conduits and the tank will be such as to produce the best results for any particular oil. Obviously, if the preservative is of less specific gravity than the washing solution, its outlet conduit will be connected to the upper portion of the tank and the levels of the drain conduits will be changed accordingly.

Depending upon the relative densities of the preservative and water and also upon the point of sludge formation, the pipe connections and position of the adjustable float and spray head may be varied to accomplish proper operation of the apparatus. For example, if the preservative is coal-tar distillate, such as creosote, having a specific gravity of 1.00 or more, the location of the pipe lines, adjustable float and spray head may be as shown in the drawing and the preservative to be processed is admitted near the top of the processing tank and the clean preservative withdrawn from the bottom of the processing tank. The sludge is slightly heavier than the water, and the heavier separated oil settles to the extreme bottom of the tank.

The processing tank shown in the drawing is an open one, operating at atmospheric pressure. This tank may, however, be a closed one, operating at some predetermined pressure. The processing tank may also be insulated for the purpose of retaining the heat within the preservative and the wash water or solution.

The time cycle of the preservative treatment may be varied as dictated by experience and will vary according to type and condition of preservative to be cleaned. It will vary from one hour to twenty hours and the operation may be intermittent or continuous, as is best suited to desired results.

Obviously, the invention is not limited to the particular embodiment herein described, as it is quite practical to vary both the form and operating cycle and yet accomplish the desired results.

What is claimed is:

1. The method of cleansing and simultaneously partially dehydrating oily wood preservatives composed of coal-tar creosote and the like which is characterized by discharging the preservative in the form of a finely divided spray into a body of water to form a temporary emulsion; permitting the emulsion to separate at different levels into water soluble constituents, insoluble constituents or sludge, and cleansed preservative; removing accumulating sludge and preservative; and replenishing the wash-water to maintain the desired liquid level.

2. The method of cleansing and simultaneously partially dehydrating oily wood preservatives composed of coal-tar creosote and the like which is characterized by discharging the preservative in the form of a finely divided spray into a body of water to form a temporary emulsion; heating the water to hasten coalescence of one of the phases of the emulsion; permitting the emulsion to separate at different levels into water-soluble constituents, insoluble constituents or sludge, and cleansed preservative; removing accumulating sludge and preservative; and replenishing the wash-water to maintain the desired liquid level.

3. The method of cleansing and simultaneously partially dehydrating oily wood preservatives composed of coal-tar creosote and the like which is characterized by discharging the preservative in the form of a finely divided spray into a body of aqueous washing solution contained in a processing tank to form a temporary emulsion;

permitting the emulsion to separate at different levels in the processing tank into constituents having difierent specific gravities containing water soluble foreign matter, insoluble foreign matter or sludge and cleansed preservative, respectively; removing the difierent constituents, including the cleansed preservative, as they accumulate; and replenishing the aqueous washing solution to maintain the desired level in the tank.

4. The method of cleansing and simultaneously partially dehydrating oily wood preservative composed of coal-tar creosote and the like having a higher specific gravity than water, which is characterized by discharging the preservative in the form of a finely divided spray into a body of aqueous washing solution having a lower specific gravity to form a temporary emulsion; permitting the emulsion to separate and settle into different strata in the washing solution; removing the sludge and insoluble settled impurities and the cleansed preservative through separated conduits communicating with the different strata; and replenishing the washing solution tomaintain the desired quantity and level of the solution.

5. The method of cleansing and simultaneously partially dehydrating oily wood preservative composed of coal-tar creosote and the like having a higher specific gravity than water, which is characterized by discharging the preservative in the form of a finely dividedspray into' a body of aqueous washing solution having a lower specific gravity to form a temporary emulsion, heating the difierent strata to temperatures ranging between 150 F. and 200 F. to hasten coalescence of one of the phases of the emulsion; permitting the emulsion to separate and settle in diflerent strata in the solution; removing the sludg and insoluble settled impurities and the cleansed preservative through separated conduits communieating with the difiernt strata; and replenishing the washing solution to maintain the desired quantity and level of the solution.

6. The method of cleansing and simultaneously partially dehydrating oily wood preservative composed of coal-tar creosote and the like which is characterized by discharging the preservative in the form of a finely divided spray through a floating spray head submerged in a washing solution of lower specific gravity to form a temporary emulsion; permitting the emulsion to settle out of the cleansed preservative in a separated stratum at the bottom of the body of the solution; removing the cleansed preservative and sludge containing the impurities through separate conduits; and replenishing the washing solution to maintain the desired liquid level. I

7. That method of cleansing and simultaneously partially dehydratingreclaimed coal-tar creosote used in preserving wood products and having a specific gravity higher than that of Water, which is characterized by delivering the creosote in the form of a finely divided spray into a quiescent body of wash-water toform a temporary emulsion; applying heat to the wash-water at different levels to hasten coalescence of one of the phases of the emulsion; permitting the emulsion to stratify into separate layers containing the water-soluble constituents, sludge containing insoluble constituents and the cleansed creosote, with the creosote accumulated at the bottom; removing the accumulated sludge and cleansed creosote separately; and replenishing the washwater to maintain the desired level in the container.

8. Apparatus for cleansing and simultaneously partially dehydrating oily wood preservatives composed of coal-tar creosote and the like comprising, in combination, a processing tank containing an aqueous Washing solution; a float in the tank on the solution; a spray head carried by the float and discharging downwardly into the solution to form an emulsion; a pump connected to deliver preservative under pressure through the spray head; drain conduits connected at different levels to the tank to remove sludge and insoluble constituents and cleansed preservative of different specific gravities and at different levels in the tank when the emulsion separates or settles in difierent strata; and a supply conduit for replenishing the washing solution and maintaining the desired liquid level in the tank.

9. Apparatus for cleansing and simultaneously partially dehydrating oily wood preservatives composed of coal-tar creosote and the like comprising, in combination, a processing tank containing an aqueous washing solution; a float in the tank on; the solution; a spray head carried by the float and discharging downwardly into the solution to form an emulsion; a pump connected to deliver preservative under pressure through the spray head; drain conduits connected at different levels to the tank to remove sludge and insoluble constituents and cleansed preservative of different specific gravities and at different levels in the tank when the emulsion separates or settles in difierent strata; separate heating means for the several strata within the tank; and a supply conduit for replenishing the washing solution and maintaining the desired liquid level in the tank.

JOSEPH A. VAUGHAN. JOSEPH C. VINSON. 

